bind.clj

;; walk-root walks the root node to a child node on firebase, e.g. /hello -> /hello/child/node
;; (walk-root root-node [:child :node])

;; bind is used like:
;; (bind root-node :value [:child :node] #(println "Changed to" %))
;;
;; (let [c (bind root-node :value [:child :node])]
;;   (go-loop [m (<! c)]
;;     (println "Changed to" m)
;;     (recur (<! c))))
;;
(defn bind
  "Bind to a certain property under the given root"
  ([root type korks]
   (let [bc (chan)]
     (pani.core/bind root type korks #(do
                                        (println "Pushing" %)
                                        (go (>! bc %))))
     bc))

  ([root type korks cb]
   (let [node (walk-root root korks)]
     (cond
       (= type :value) 
       (.addValueEventListener node
                               (reify com.firebase.client.ValueEventListener
                                 (onDataChange [this v]
                                   (cb (.getValue v)))))

       (= type :child_added)
       (.addChildEventListener node
                               (reify com.firebase.client.ChildEventListener
                                 (onChildAdded [this v _]
                                   (cb (.getValue v)))))
       :else (throw (Exception. (str type " is not supported")))))))